1. Field of the Invention
The present invention relates to an autostereoscopic display, and more particularly, to an autostereoscopic display which allows conversion between a two-dimensional (2D) mode and a three-dimensional (3D) mode without a decrease in resolution and is manufactured as a flat panel for television, computer graphics, and other applications.
2. Description of the Related Art
An effective method of providing a stereoscopic image through a flat panel display is a lenticular method using a lenticular lens array located between an image panel and a viewer to separate a viewing zone of a left eye image from a viewing zone of a right eye image in a stereopair. In the lenticular method, a right eye image and a left eye image are provided to the viewer's right and left eyes, respectively. Conventionally, two images of the stereopair are displayed on one image panel such that one set of columns, e.g., odd columns, displays a left eye image and another set of columns, e.g., even columns, displays a right eye image. Since the left eye image and the right eye image are displayed on one panel, the resolution of each image is half of the resolution of the panel.
The recent development of a liquid crystal display (LCD) panel with fast response facilitates the display of a stereoscopic image with a full resolution of the panel by using a frame-sequential operation, and continuously alternately displaying a left eye image and a right eye image. Here, both of the left eye image and the right eye image are displayed with the full resolution of the display panel. To display a frame sequentially, a unit for selectively switching and displaying the left eye image and the right eye image is needed.
FIG. 1 illustrates a prior autostereoscopic display disclosed in U.S. Pat. No. 5,457,574. The prior autostereoscopic display includes an LCD panel 11 forming an image, a lenticular lens sheet 12 separating a viewing zone of a left eye image and a viewing zone of a right eye image, first and second light sources 13a and 13b connected to a light source controller 14 to be switched on and off, and an image signal controller 15 transmitting an image signal to the LCD panel 11.
The first and second light sources 13a and 13b alternately emit light in synchronization with a frame generation rate of the LCD panel 11. The light from the light source 13a or 13b is converged into a vertical line (i.e., a column) of the LCD panel 11 by the lenticular lens sheet 12. In other words, a pixel column is displayed by the lenticular lens sheet 12. This process results in the generation of two sets of light lines, each of which is displayed as a pixel column by the lenticular lens sheet 12. Each of an observer's eyes 16a and 16b alternately sees an image through odd sets of columns and even sets of columns when the first and second light sources 13a and 13b are alternately turned on and off. One of the eyes, 16a or 16b, sees the light lines serving as backlight first behind the odd, then behind the even sets of columns of the LCD panel 11, while the other eye sees an image first through the light lines behind the even, then behind the odd sets of the columns. The image signal controller 15 rapidly changes the left and right eye images displayed on the odd and even columns and generates synchronization signals for the light source controller 14 to synchronize the switching of the light sources 13a and 13b. As a result, the observer sees a full set of LCD pixels and an image with the full resolution of the LCD panel 11.
The above-described prior technology is based on a directional backlight which is usually very thick and is more complicated to manufacture than a conventional diffuse backlight for an LCD. The directional backlight includes at least two separate light sources or a single light source having a diagram array that can be switched such that an effective horizontal position of a light source can be shifted in synchronization with the provision of graphic data. Since the position of a viewing zone is determined by the position of a light source, each of a viewer's eyes can alternatively perceive an image displayed through different sets of pixels, and therefore, the viewer can see a full-resolution image. However, the prior technology based on the directional backlight has drawbacks due to complicated manufacturing and large size.